fix: make OAuthProviderOptions generic over Env type

[mattzcarey]

Summary

Makes OAuthProviderOptions<Env> generic to properly thread the Env type through handler types, eliminating TypeScript errors when using typed environments.

Changes

• OAuthProviderOptions<Env> — now generic, threading Env through all handler types
• ExportedHandlerWithFetch<Env> and WorkerEntrypointWithFetch<Env> — accept generic parameter
• TypedHandler<Env> — discriminated union now generic
• OAuthProvider<Env> class — generic, passes Env to internal implementation
• getOAuthApi<Env>() function — now generic
• Default changed from Env = any to Env = Cloudflare.Env (per reviewer feedback)

Why Cloudflare.Env as the default?

• Aligns with Cloudflare's patterns — WorkerEntrypoint<Env = Cloudflare.Env> uses the same default
• Works with wrangler types — generates interface Env extends Cloudflare.Env {}, which is compatible
• No any in public API — addresses reviewer feedback about explicit any
• Backwards compatible — existing code without explicit Env continues to work

Problem

When using typed environments in Cloudflare Workers, passing handlers with typed Env to OAuthProviderOptions caused TypeScript errors because the handler types used non-generic ExportedHandler. This required @ts-expect-error workarounds.

Solution

By making OAuthProviderOptions generic over Env (defaulting to Cloudflare.Env), the type system properly threads the environment type through to all handler types.

Example Usage

// Option 1: Inferred from handlers (most common with wrangler types)
const provider = new OAuthProvider({
  defaultHandler: myHandler,  // Env inferred from handler type
  apiHandler: myApiHandler,
  // ...
});

// Option 2: Explicit generic for custom Env
interface MyEnv {
  OAUTH_KV: KVNamespace;
  API_SECRET: string;
}

const provider = new OAuthProvider<MyEnv>({
  defaultHandler: myHandler,
  apiHandler: myApiHandler,
  // ...
});

Fixes #71

Test Plan

• npm run typecheck — all types check successfully
• npm run test — all 216 tests pass
• npm run prettier — code formatted correctly
• Verified with real Cloudflare Worker project using wrangler types
• Tested all user scenarios: custom Env, wrangler-generated Env, augmented Cloudflare.Env

[changeset-bot]

🦋 Changeset detected

Latest commit: e4198a0

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@cloudflare/workers-oauth-provider	Patch

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commit: e4198a0

[threepointone]

straightforward. don't love the explicit any, but fixing that would be a much bigger refactor.

[mattzcarey]

straightforward. don't love the explicit any, but fixing that would be a much bigger refactor.

happy to make it default to Cloudflare.Env